NIR‐responsive nanomaterials and their applications; upconversion nanoparticles and carbon dots: a perspective

Abstract

Near‐infrared (NIR) light responsive materials have received much attention for diverse applications due to their excellent optical properties. This type of material exhibits upconverted luminescence, a non‐linear optical process in which two or more low energy photons, usually from NIR light irradiation are transformed to high energy photons emission through energy transfer upconversion, excited state absorption, photon avalanche or multiphoton absorption. The NIR range of excitation source is favorable for biological imaging and cancer theranostic applications due to their high penetration depth, low autofluorescence, minimal light scattering, reduced photodamage, and negligible phototoxicity. Having these properties, NIR responsive materials such as upconversion nanoparticles (UCNPs) and carbon dots (CDs) which perform upconversion luminescence are actively exploited in a wide variety of applications such as display and sensory technology. While CDs are well known for their versatility in using different chemicals and green precursors to achieve tunable optical properties, UCNPs also have the advantage that a continuous‐wave NIR laser can be used as the excitation source. This article reviews the properties of these two materials in the aspects of luminescence mechanisms and their recent developments in cancer theranostics, display technology, biosensing and metal ions sensing applications. © 2018 Society of Chemical Industry

NIR laser scanning microscopy for photophysical characterization of upconversion nanoparticles and nanohybrids

“…11,12 Owing to their exceptional properties, UCNPs are promising in a wide range of applications e.g., (bio)sensing, solar cells, theranostics, and bioimaging. [13][14][15][16][17] Although NIR-LSM was not initially conceived to be used with UCNPs, this technique has been adapted perfectly to imaging them since their absorption and the NIR-LSM excitation occur in the same region (specifically, in the NIR). 18,19 Moreover, the long lifetime of UCNP emissions makes it possible to avoid the undesirable auto-fluorescence from the sample by using a simple time-gating technology.…”

Detecting Ferric Iron by Microalgal Residue-Derived Fluorescent Nanosensor with an Advanced Kinetic Model

“…But the efficiency of most of these are largely debatable because of the severe fluorescent decay and complex modification procedures (Chao et al, 2013). Instead, CQDs are composed of graphitic microcrystalline cores with sp 2 hybridization and abundant surface area bearing polar functional groups (Chien et al, 2018). Recent reports have demonstrated that CQDs possess varied application potential owing to the characteristics of low toxicity, high water solubility, environmental compatibility, biocompatibility, and low photobleaching (Lim et al, 2015;Shamsipur et al, 2017;Zhang et al, 2019).…”

Carbon Dot-functionalized Interferometric Optical Fiber Sensor for Detection of Ferric Ions in Biological Samples

“…Carbon-dots, also known as carbon nanoparticles, are the latest addition to the carbon-based fluorescent nanomaterial family and have been increasingly popular due to their attractive properties such as facile synthesis, biocompatibility, good aqueous stability, and unique optical characteristics. 5 Carbon-dots favor a broad range of applications such as sensing, cellular imaging, cancer therapeutics, optoelectronics, and others. 6 The potential use of carbon-dots (CDs) for iron detection has been demonstrated in many recent works.…”